Molding apparatus



Jan. 13, 1948. F. A. SCHULTZ MOLDING APPARATUS 2 Sheets- Sheet 1 FiledOct. 6, 1944 I/VVE/VTOR 5450190472 A ram/7 ill/j F. A. SCHULTZ MOLDINGAPPARATUS Jan. 13,

2 Sheets-Sheet 2 Filed Oct. 6, 1944 TY \YTT M VE/VMR A 54.60/04 72 YATTORA/f) Patented Jan. 13,

UNITED STATES PATENT OFFICE 2,434,594 7 Mom-rho rhinos. Frank A.Schultz, La o ge m, assignor to Western Electric compan Incorporated;New

York,;l\ Y., a corporation of New'Yoi'k Aim if tiqh more 6. 1 4 Se a No?M 2*. Glaims. 1

This invention relates to molding apparatus andmore particularly to. aninjection type molding apparatus.

The present invention is particularly useful in the molding ofrelatively long tubes having one closed end wherein great. diflioult-yis experienced in holding a long core concentricv in a die' cavity inorder to prevent its deflection during the in jection operation, whichdeflection results in de fective tubes.

An object of; this invention is. to provide asimple,- efi icient andpracticable apparatus for molding hollow articles.

In accordance Wi t e above object. the present invention; in oneembodiment thereof, comprises a sectionalmol ng die, one section ofwhidh s Q le o a a ta i nary sec? and th two e tions Tre ormed to. rovida e Cavity hwa t n l li iq the ect ons e te di g l n tu allro t e. d ecav ty. Eemovably a a hed to t emqvable ie s ction is a relatively longcorehaving an integral di e por: tion and arranged above and spaced fromthe upper end of the cdre is a depending die member, which, n ddii fi'iit e d e v t'yip j'e. and die portion, serves to'. provi e a mold forrelatively long time havin a closed iibiier end. Slidably fitted oh thecore and on the with ofthe die cavity is rms, which is fie'ctive toprevent deflection the one. this holding it con' with the die cavitywhich surround t e V t e i j d m lld fifl' ia fills" the l me, th ringbeing finally pushed on of theoore'and into a recess surrounding thedependingdi Other objects and advantages of th' will more-fully appearfrom thefollow 7 a description, taken in; conjunction with the do:companying drawings, in which Fig. 1 is afront' elevational view, partlysec? tion, of the movable die section" (it a molding ap aratus embodyingthe features of this mvehtion, the view being taken onthe parting" lineoi the die sections with the parts t ar'ndrmar positions prior to theiniieotion ofthe" molding material; W

- Fig. 2 isa vertlcal-sectionalview" taken on the" line 2-2 of Fig. 1,sl'io'wir'ig the position of the parts after completion of a moldingoperation;

Fig. 3 is a plan sectional View taker-l on th'line 33' of Fig. 2,showing the position of the parts prior to the injection of the moldingmaterial;

Fig. 4 is a fragmentary enlarged vertical see tional view of the upperportion ofFig. 2, show ing the position of the parts prior toth'inle'ction. of the molding material; and

2 Fig. 5 is a plan sectional view taken on the line 5 5 of Fig. 4.

Referring now to the drawings, wherein the features of "this inventionhave been embodied in a horizontal type molding apparatus, a Sta die,section being indicated at In and. av tally reciprocablef die section atll. The die S tibn ll] i's alttalched, as indicated at 12, to a fliedbed l3 and the die section u is attached, as indicated at [4, to areciprocatory platen, 5 oji the apparatus, a vertical partingline of thedie S b i's ifi iqi fi a1 Fig l a d .1-,

entit s d ed c sses, S a d 2 med n" he. die ,QI1S.. m an if. nective rat ach e it the a t ng, he. i i. i i fill 46 ie se ions are in abut relan fillies? 2 8 and. or t n a a n a an: dated in general at 2}.lie'niovably fitt d in the i a ity 21 s a cor m m h in mi i her w th. ildsr si di b n 250 1. 6 92 and. ie grt o ei ene l i. ullar i was: ctnlThe r i Qf fie'd P fiwh sh. is of the greatest, diameter- 1st dsimilarly arranged bottom sloping f es 25 (Figs; land which" may engagesimilarly arranged and sloping face 2'! of the recesses 19 and Z0 intheare stations [0 and n, respects/aye xtending from the dle portion 2 5'at dia-1 metrically opposite points and o'ffset with respect to thelongitudinal c'en'terline ofth'e core 22 and die portion 25 are lugs 28ente'rable' in' re'cess's 29 in the die section H], which, incooperation with a recess 32 provided in one of the sloping faces 26 ofthe die portion and a spring'press'ed' pin 33 mounted in the die sectionII, m ke it possible to mount the core 2 2'a'nd its die portion 25 inonly one position in the recess 20 ofthe die section H. The m 33 alsoserves to retain the core 22 on the die-section H until freedtherefromin a manner to be described hereinafter.

sli'dably fitted upon the core 22 and on the wall of the die cavity 2|is a sleeve orring 34', which is provided on its periphery withlongitudinal slots 35' for air venting purposes. The purpose of theringwill be fully described here in'after. In the upper shouldered end ofthe die cavity 2i is' r'emovabl'y fitted a shouldered die member 36 ofcircular cross section having a' lower depending portion 31 (Figs. 1 and4), the diameter of which is slightly less than that of the core 22,so'that an annular recess 38 is formed between the die's'ection's HI"and II and theportion 3'! of the die'meniher 36 directly above the upperendface of the core 22 for a purpose to be described hereinafter. Thespace between the upper end face of the core 22 and the lower end faceof the die member portion 31 determines the thickness of the closedupper end wall of a tube 39, shown in Fig. 2, upon completion of amolding operation. Formed in the die member 36 is a shouldered aperture46, in the lower larger diameter of which is fitted a pair ofsemi-cylindrical inserts 4|, each having a slot 42 ground into its fiatinner surface and extending longitudinally along the insert from end toend. As

shown, the slots 42 taper outwardly slightly along their entire lengthto facilitate the removal of excess molding material entered therein.The aperture, which is rectangular in cross section, provided by theslots 42 and opening at its upper end into the smaller diameter of theaperture 40 of the die member 36, serves as an outer air ventingaperture. An air venting aperture which is rectangular in cross sectionis desirable since it permits control of the thickness of the aperturewhile, at the same time, allowing control of the width.

A leaf spring 45, fixed to the die section II and engaging, at its outerfree end, the upper surface of the die member 36, serves to maintain thedie member in position in the recess 26 of the die section II when thelatter die section is moved away from the die section I6 after a moldingoperation. This arrangement also lends itself to the ready removal ofthe die member 36 when necessary.

A horizontally disposed tapering sprue chamber 46 is formed in ahardened insert 41 secured in the die section It] (Fig. 3) to admitmolding material from a movable extrusion head 48, shown fragmentarily.A runner 49 formed jointly in the die sections l6 and II extendslaterally on the parting line l8 of the die sections from the innerlarger end of the sprue chamber 46 to the die cavity 2|, where itcommunicates with a bifurcated runway 50 formed jointly in the uppersurface of the die portion 25 of the core 22 and in the abutting surfaceof the die sections I and H, whereby the molding material may pass intothe die chamber and rise to the upper end of the core 22 under theextrusion pressure. This drives any trapped air or gas upwardly and itescapes first through the slots 35 of the ring 34 and thence through theventing aperture formed by the tapering slots 42 of the inserts 4|carried by the die member 36 and finally through the smaller diameter ofthe aperture 40 of the die member 36 to atmosphere.

To facilitate removal of the core 22 and its die portion 25 with themolded tube 39 thereon from the die section [I after the separation ofthe die sections, a manually actuated lever 53 is provided. The lever 53is mounted in a slot 54 formed in the die section II at the parting linel8 and is fulcrumed for lateral movement about a pin 55 attached to thedie section and entered in an aperture in the lever, the aperture andthe slot 54 being relieved, as indicated at 56 and. 51, respectively, topermit the necessary lateral movement of the lever. A strap 60 securedto the die section II and spanning the lever 53 serves to limit themovement of the lever in one direction about the pin 55, a recess 6|being formed in the die section III for receiving the strap when the diesections are closed. The inner end of the lever 53, when the diesections l0 and H are closed (Fig. 3), abuts one of the lugs 28 providedon the die portion 25 of the core 22. Upon the die section being movedto the left (Fig. 3) to separate it from the die section 10, the core22, with 4 its die portion 25, will be carried therewith, thespring-pressed pin 33 and the leaf spring 45 insuring that the core, aswell as the die member 36, will not stay with the stationary die sectionIt). Thereafter, in order to free the core 22 from the die section II,the hand lever 53 i laterally rocked clockwise about the pin 55,whereupon the inner end of the lever bearing upon the lug 26 on the dieportion 25 of the core 22 loosens it from the spring-pressed pin 33, aswell as from the die secjjtion, after which it may be manually removedfrom the apparatus. The manner of mounting the core 22 and the diemember 36 in the die section I |,it is believed, will be clearlyunderstood from the above description.

It will be evident that, in the molding of the long tube 39, having aclosed end wall, difficulty will be encountered in maintaining the longcore 22 concentric in the die cavity 2| even when the best steel is usedto form the core unless some means is provided for preventing deflectionof the core in the die cavity. This is the purpose of the sleeve or ring34 slidably fitted upon the core 22 and the peripheral wall of the diecavity 2| and the cooperating annular recess 38 arranged between thedepending portion 31 of the die member 36 and the die cavity. Althoughthe ring 34 is shown in Figs. 1 and 4 as adjacent the upper end of thecore 22 when the apparatus is in condition for a molding operation, itwill be understood that it is not necessarily confined to this position,but may be positioned at any point along the core.

In the operation of the apparatus above described, the molding material,in the manner previously described, is entered in the die cavity 2|under the extrusion pressure and rises therein, pushing the ring 34upwardly and finally pushing it on of the core and into the recess 38,as shown in Fig. 2, as the end wall of the tube 39 is formed between thecooperating surfaces of the core, die member 36 and the ring 34. Thisarrangement of supporting the core 22 during the molding of the tube 39accurately maintains the core concentrically in the die cavity 2| andthus results in a straight tube with a uniform wall thickness. Uponcompletion of the molding operation, the die section II is moved awayfrom the die section III and the core 22 freed from the die section IIin the manner hereinbefore described, the molded tube 39 being removedtherefrom. To remove the ring 34 from the die member 36, the latter isfreed from the die section II and the ring slipped off the die memberand then is slipped onto the upper end of the core 22. Thereafter thecore 22 and the die member 36 are placed in position in the recess 26 ofthe die section II, as shown in Fig. 1, and after closing the diesections, another tube may be molded.

What is claimed is:

1. In a sectional molding die for molding hollow articles, cooperatingstationary and movable die sections having formed jointly therein a diecavity, a core mounted in and spaced from the wall of said cavity at oneend, said core having an enlarged die and base portion at its other endnormally supported in enlarged portions of said cavity, said core baseportion and said stationary die section having cooperating portions soconstructed and arranged that said core may be mounted only in oneoperative position. means mounted in said movable die section andcooperating with a face on said core base portion for retaining saidcore thereon upon separation of said die sections, a lever pivoted onsaid movable die section bearing at its inner end on one of saidcooperating portions on said core base portion for freeing the core fromsaid movable die section upon separation of said die sections, and anapertured member surrounding and slidable upon said spaced core end andexternally upon the wall of said cavity for maintaining said core end inpredetermined position in said cavity during the molding of an article.

2. In a sectional molding die for molding hollow articles, cooperatingstationary and movable die sections having formed jointly therein a diecavity, a core mounted in and spaced from the wall of said cavity at oneend, said core having an enlarged die and base portion at its oppositeend normally supported in enlarged portions of said cavity, said corebase portion and said stationary die section having cooperatingextensions and recesses, respectively, so arranged that said core may bemounted only in one operative position, a lever pivoted on said movabledie section hearing at its inner end on one of said extensions forfreeing the core from said movable die section upon separation of saiddie sections, an apertured member surrounding and slidable upon saidspaced core end and externally upon the wall of said cavity formaintaining said core end in predetermined position in said cavityduring the REFERENCES CITED The following references are of record inthe file of this patent:

UNITED STATES PATENTS Number Name Date 2,351,454 Pereles June 13, 19441,816,011 Gurnee July 28, 1931 2,027,165 Grubman Jan, 7, 1936 2,370,294Dodge Feb. 27, 1945 FOREIGN PATENTS Number Country Date 388,662 GreatBritain Mar. 2, 1933 OTHER REFERENCES Ser. No. 391,198, Chapuis (A. P.(3.), pub. June 15, 1943.

